Method of making a transducer with improved inductive coupling

Abstract

A thin film magnetic transducer is formed in a plurality of layers and comprises a yoke with at least one arm having segments respectively lying in separate said layers and connected through a transition layer, and one or more coils; the coil (or coils) and the yoke are intertwined to provide more than two flux interactions therebetween. In one aspect, the segments of the arm are oriented obliquely to each other and have easy axes of magnetization respectively transverse to the directions of flux conduction through said segments, and the segments are joined together so that flux can pass between them without flowing parallel to the easy axis of any of the segments.

I claim: 
     
       1. A process for fabricating a thin film magnetic transducer in a plurality of layers and that includes a coil having a plurality of turns, comprising forming a yoke that includes at least one arm having segments respectively lying in separate said layers,   disposing at least one of said segments generally along a longitudinal axis of said transducer and providing said segment with an easy axis of magnetization oriented transverse to a direction of flux conduction through said segment and at an oblique angle to said longitudinal axis, and   connecting a plurality of said segments through a transition layer to intertwine said yoke with said coil and provide more than two flux interactions between said yoke and each one of said turns.   
     
     
       2. The process of claim 1 further comprising disposing each one of said segments generally along said longitudinal axis and providing each one of said segments with an easy axis of magnetization oriented transverse to a direction of flux conduction through said segment and at an oblique angle with respect to said longitudinal axis, whereby said yoke conducts flux predominantly by rotation rather than by wall motion. 
     
     
       3. The process of claim 1 wherein said coil lies at least in part in said transition layer. 
     
     
       4. The process of claim 1 further comprising forming a second arm of said yoke, said second arm having segments respectively lying in separate said layers, connecting said segments of said second arm through said transition layer, and   connecting said second arm to said one arm to form a flux path with a storage medium.   
     
     
       5. The process of claim 4 further comprising connecting a segment of said second arm to a segment of said one arm through said transition layer. 
     
     
       6. The process of claim 1 wherein said yoke includes a single said arm constructed to form a flux path with a storage medium. 
     
     
       7. The process of claim 6 wherein said arm includes a tip arranged to be disposed adjacent to a storage medium and further comprising the step of providing said arm with a region constructed to cause flux in said arm to be radiated from said arm by said region. 
     
     
       8. The process of claim 1 further comprising disposing said at least one segment at an oblique angle with respect to said longitudinal axis and orienting said easy axis generally perpendicular to said segment. 
     
     
       9. The process of claim 2 further comprising disposing each one of said segments at an oblique angle with respect to said longitudinal axis and orienting said easy axis of each one of said segments generally perpendicular thereto. 
     
     
       10. The process of claim 4 further comprising disposing each one of said segments of said second arm generally along said longitudinal axis and orienting an easy axis of magnetization of said each segment of said second arm transverse to a direction of flux conduction through said segment and at an oblique angle with respect to said longitudinal axis, whereby said second arm conducts flux predominantly by rotation rather than by wall motion. 
     
     
       11. The process of claim 10 further comprising disposing each one of said segments of said second arm at an oblique angle with respect to said longitudinal axis and orienting said easy axis of said segment generally perpendicular thereto. 
     
     
       12. A process for fabricating a thin film magnetic transducer that includes a coil, comprising forming a yoke that includes at least one arm having a plurality of elongated segments,   arranging said elongated segments obliquely to each other and providing each said segment with an easy axis of magnetization oriented transverse to the direction of flux conduction through said segment, and   joining said segments together to intertwine said yoke with said coil to provide more than two flux interactions therebetween, and to cause flux to pass between said interconnected segments without flowing parallel to the easy axis of said segments.   
     
     
       13. The process of claim 12 further comprising forming said transducer in a plurality of thin film layers so that said oblique segments lie in separate said layers, and   joining said segments together through an intermediate portion extending between said layers.   
     
     
       14. The process of claim 12 further comprising forming said transducer in a plurality of thin film layers with said oblique segments lying in separate said layers, and   joining said segments together through a transition layer, said coil lying at least in part in said transition layer.   
     
     
       15. The process of claim 12 further comprising orienting the easy axis of each one of said segments perpendicular to a direction along which said segment generally extends. 
     
     
       16. The process of claim 12 further comprising forming a second arm of said yoke, said second arm having a plurality of elongated segments,   arranging said elongated segments obliquely to each other and providing each said segment with an easy axis of magnetization that is transverse to the direction of flux conduction through said segment,   joining said segments of said second arm together so that flux can pass therebetween without flowing parallel to the easy axis of said segments, and   connecting a segment of said second arm to a segment of said one arm so that flux can pass therebetween without flowing parallel to the easy axis of said segments.   
     
     
       17. The process of claim 16 further comprising forming said transducer in a plurality of thin film layers so that said oblique segments of said second arm lie in separate said layers, and   joining said segments of said second arm together through an intermediate portion extending between said layers.   
     
     
       18. The process of claim 16 further comprising forming said transducer in a plurality of thin film layers with said oblique segments of said second arm lying in separate said layers, and   connecting said segments of said second arm together through a transition layer, said coil lying at least in part in said transition layer.   
     
     
       19. The process of claim 16 further comprising orienting the easy axis of each one of said segments of said second arm perpendicular to a direction along which said segment generally extends. 
     
     
       20. The process of claim 16 further comprising forming said transducer in a plurality of thin film layers with said oblique segments of each one of said arms lying in separate said layers so that the segments that are disposed in a first one of said layers extend generally in a first direction and have easy axes of magnetization perpendicular to said first direction, and the segments that are disposed in a second one of said layers extend generally in a second direction oblique to the first direction and have easy axes of magnetization perpendicular to said second direction.   
     
     
       21. The process of claim 16 further comprising intertwining said segments with said coil to provide four flux interactions between said coil and said yoke. 
     
     
       22. The process of claim 12 wherein said yoke comprises a single said arm, and further comprising intertwining said segments with said coil to provide three flux interactions between said coil and said yoke. 
     
     
       23. The process of claim 22 further comprising configuring said arm to have a portion of relatively small surface area adapted to be disposed adjacent to a storage medium and transfer flux between said arm and said medium, and a portion of a relatively large surface area to cause flux in said arm to be radiated from said arm to regions adjacent to said transducer. 
     
     
       24. The process of claim 12 further comprising orienting an easy axis of magnetization of each one of said segments at an oblique angle with respect to a longitudinal axis of said transducer. 
     
     
       25. The process of claim 12 further comprising orienting the easy axis of magnetization of at least one of said segments at an oblique angle relative to the easy axis of another one of said segments. 
     
     
       26. A process for forming a yoke of a magnetic transducer and inducing an easy axis of magnetization in said yoke by applying a magnetic field thereto, comprising the steps of providing a substrate on which said yoke will be formed, said substrate being disposed generally along an axis,   positioning said substrate to provide an oblique angle between said axis and a first direction,   forming a segment of said yoke that extends along said first direction on said substrate while said substrate is positioned at said angle to arrange said segment at said angle with respect to said axis, and   applying said magnetic field with said substrate positioned at said angle to induce said easy axis of magnetization in said segment.   
     
     
       27. The process of claim 26 wherein said segment is formed by depositing ferromagnetic material on said substrate. 
     
     
       28. The process of claim 27 further comprising applying said magnetic field during said depositing. 
     
     
       29. The process of claim 26 further comprising applying said magnetic field in a selected direction that is transverse to said first direction. 
     
     
       30. The process of claim 29 wherein said selected direction is perpendicular to said first direction. 
     
     
       31. The process of claim 26 further comprising selecting said direction of said magnetic field and said angle to dispose said easy axis at a predetermined orientation with respect to the extent of said segment. 
     
     
       32. The process of claim 31 further comprising annealing said segment after said easy axis is induced, said annealing possibly causing said orientation of said easy axis to change, and   controlling said annealing to minimize said change in said orientation.   
     
     
       33. The process of claim 32 wherein said annealing includes heating said segment at a nominal temperature, and wherein said controlling includes using a temperature below said nominal temperature for said heating. 
     
     
       34. The process of claim 31 further comprising annealing said segment after said easy axis is induced, said annealing possibly causing said orientation of said easy axis to change, and   selecting said direction of said magnetic field and said angle to compensate for said change in said orientation.   
     
     
       35. The process of claim 26 wherein said segment comprises ferromagnetic material, and further comprising annealing said ferromagnetic material after said segment is formed. 
     
     
       36. The process of claim 35 wherein said annealing includes heating said segment in a range of 150° Centigrade to 300° Centigrade. 
     
     
       37. The process of claim 35 wherein said annealing includes heating said segment in a range of 225° Centigrade to 265 Centigrade. 
     
     
       38. The process of claim 35 wherein said annealing includes heating said segment at 260 Centigrade. 
     
     
       39. The process of claim 35 further comprising forming a coil for said yoke and supported by said substrate and separating said coil from at least a portion of said yoke segment with a first material, and   heating said first material to cause said first material to serve as an electrical insulator between said coil and said yoke segment, said heating also serving to perform at least a portion of said annealing.   
     
     
       40. The process of claim 26 further comprising positioning said substrate to provide a second oblique angle between said axis and said first direction,   forming a second segment of said yoke along said first direction on said substrate while said substrate is positioned at said second angle to arrange said segment at said second angle with respect to said axis, and   applying said magnetic field with said substrate positioned at said second angle to induce said easy axis of magnetization in said second segment.   
     
     
       41. The process of claim 40 further comprising forming said second segment so that at least a portion thereof intersects a portion of the first-formed segment, and   joining said segments together where they intersect.   
     
     
       42. The process of claim 40 wherein said transducer is formed in a plurality of thin film layers on said substrate, further comprising forming the first-formed segment and said second segments in separate said layers that are separated by a transition layer, and   joining said segments together through said transition layer.   
     
     
       43. The process of claim 40 further comprising annealing each one of said segments. 
     
     
       44. The process of claim 43 wherein said annealing of said second segment possibly induces a change in orientation of said easy axis of the first-formed segment, and further comprising controlling said annealing of said second segment to minimize said change in said easy axis orientation of the first-formed segment.   
     
     
       45. The process of claim 44 wherein the first-formed segment is annealed by heating at a first temperature, said controlling includes using a second temperature below said first temperature to anneal said second segment. 
     
     
       46. The process of claim 45 wherein said first temperature is 260° Centigrade and said second temperature is 200° Centigrade. 
     
     
       47. The process of claim 43 wherein said annealing of said second segment possibly induces a change in orientation of said easy axis of the first-formed segment, and further comprising selecting a direction of said magnetic field and said oblique angle for the first-mentioned segment to compensate for said change in said easy axis orientation.   
     
     
       48. The process of claim 40 further comprising annealing said segment after said easy axis is induced, said annealing possibly causing said orientation of said easy axis to change, and   selecting a direction of said magnetic field and said first direction to compensate for said change in said easy axis orientation.   
     
     
       49. The process of claim 40 further comprising forming a plurality of the first-formed segments with said substrate oriented at said oblique angle,   forming a plurality of said second segments with said substrate oriented at said second oblique angle, and   selectively interconnecting said segments to form said yoke.